With the increasing stress on peak demand power consumption, Thermal Energy Storage (TES) has been utilized to shift power consumption from on-peak to off-peak times and rates. A need exists for load shifting from peak to off-peak periods to stabilize and improve electrical power grid efficiency without impacting the end-user. Current thermal and non-thermal appliance units having energy storage systems have had limited success due to several deficiencies, including reliance on batteries which are inherently inefficient and water chillers that are practical only in large commercial buildings and have difficulty achieving high-efficiency.
In order to provide efficiency to the overall performance of an electric power grid (EPG), energy storage may have a significant ability to shift load away from periods of peak demand. Because electric power is primarily drawn from the EPG by millions of small to medium sized electrically driven units, the overall efficiency of the EPG may be significantly influenced by the performance of these electrical devices if they could act in concert to do so. However, the size of these smaller assets makes this difficult. Not only is the magnitude of their potential on-peak offset small, but the “shape” of that offset over time and various conditions may be irregular.
Systems for providing stored thermal energy have been previously contemplated in U.S. Pat. No. 4,735,064, U.S. Pat. No. 5,225,526, both issued to Harry Fischer, U.S. Pat. No. 5,647,225 issued to Fischer et al., U.S. Pat. No. 7,162,878 issued to Narayanamurthy et al., U.S. Pat. No. 7,854,129 issued to Narayanamurthy, U.S. Pat. No. 7,503,185 issued to Narayanamurthy et al., U.S. Pat. No. 7,827,807 issued to Narayanamurthy et al., U.S. Pat. No. 7,363,772 issued to Narayanamurthy, U.S. Pat. No. 7,793,515 issued to Narayanamurthy, U.S. patent application Ser. No. 11/837,356 filed Aug. 10, 2007 by Narayanamurthy et al., application Ser. No. 12/324,369 filed Nov. 26, 2008 by Narayanamurthy et al., U.S. patent application Ser. No. 12/371,229 filed Feb. 13, 2009 by Narayanamurthy et al., U.S. patent application Ser. No. 12/473,499 filed May 28, 2009 by Narayanamurthy et al., U.S. patent application Ser. No. 12/335,871 filed Dec. 16, 2008 by Parsonnet et al. and, U.S. Provisional Patent Application No. 61/470,841 filed Apr. 1, 2011 by Parsonnet et al. All of these patents and applications utilize TES to shift air conditioning loads from peak to off-peak electric rates to provide economic justification and are hereby incorporated by reference herein for all they teach and disclose.